There are many types of sludge with widely different properties. Different users have different treatment requirement for sludge treatment. Therefore, it is difficult to achieve low cost and low emissions with a single sludge treatment process and processing line. So some people come up and ask what process and processing line is the best to use to treat sludge. This question is really hard to answer. Several sludge treatment processes commonly used in the world include hot water washing, pyrolysis ( thermal desorption or thermal decomposition), solvent extraction, incineration and biodegradation. The sludge raw materials and working conditions applicable to each process are different.
Hot water washing process has the widest applicability, suitable for tank bottom sludge, ground sludge, barge washing sludge, bag oil, oil-containing adsorption materials (such as oily clay, diatomaceous earth, etc.), oil sand, refinery sludge, steel mill rolling sludge, etc. , the key point is demulsification. Demulsification usually includes thermal demulsification, mechanical demulsification, chemical demulsification, electromagnetic ultrasonic demulsification and other methods or combinations. The disadvantage of the hot water washing process is that it cannot use its density difference to separate asphaltene, aged oil or polymers whose density is close to or greater than water.
Solvent extraction can solve the shortcomings of the hot water washing process and separate the high-density organic matter in the sludge to the greatest extent. However, the solvent extraction process often requires a solvent recovery system. The steps of maximizing solvent recovery, continuous sludge extraction, continuous separation and drying, and selecting appropriate extraction agents are relatively difficult for most companies that have not engaged in formal chemical industry.
In this case, simple batch pyrolysis plant became popular. Sludge pyrolysis plant is basically divided into several types like stationary pyrolysis plant, rotary batch pyrolysis plant and continuous pyrolysis plant. The advantage of pyrolysis process is that it can decompose most of the organic matter (crude oil, polymers, gloves, plastic bags, etc.) in the sludge at high temperature and separate these organics from the sludge. It is suitable for all sludge raw materials. Its disadvantages are high energy consumption, high emissions, and poor operation. The cost is high and most of the continuous sludge pyrolysis plant at high cost has a high failure rate and does not work properly.
Microbial degradation is a new sludge treatment process developed in recent years. Low cost, complete degradation of organic matter. However, biological bacteria often have strict requirements on the living environment. Once the sludge does not meet the specific biological flora breeding environment due to salt, acid, alkali, polymer, temperature and other indicators, it will not be able to complete degradation. In other words, microbial degradation has high requirements on the type, nature and environment of sludge, which seriously limits the promotion and application of microbial degradation technology in the sludge treatment industry.
Based on the actual situation of the industry, our company recommends the use of hot water washing plus continuous pyrolysis (or drying) process for oil sludge treatment, which is not only applicable to most oil sludges, but also can effectively reduce equipment investment, energy consumption costs and pollution emissions. The high-frequency pulse demulsification, continuous pyrolysis, high COD organic sewage treatment equipment, gasification high-temperature combustion and other equipment developed by our company can process different sludges at low cost, avoid the use of dangerous processes and dangerous equipment, and solve the difficulties in the sludge treatment industry.
